the video in the description says I am accelerating even though I am sitting perfectly still on the ground. I don't get it. Can someone please explain this?

https://www.youtube.com/watch?v=NblR01hHK6U

I don't think I'm accelerating, You need an energy input to accelerate.

the video also says the ground accelerates UPWARDS.

I don't get it. If the ground really did accelerate upwards, dropping an apple here and in china at the same time would cause the earth to accelerate in either direction equally, and the apples would never fall.

please explain me...